Automatic telephone system



March 24. 1925.

W. T. POWELL AUTOMATIC TELEPHONE SYSTEM s Sheets-She 1 iled Aug 21, 922

F l l l 1 L OVERFLOW 5 COMMON To EXCHANGE.

0V ERF'LOW TERM\NALS INVENTOR N\NFRED T. POWELL.

ATTORNEY March 24. 1925. 1,531,2I9

W. T. POWELL AUTOMATIC TELEPHONE SYSTEM Filed A 8 Sheets-Shee't 2' bmwwwsm SHLLVHHMMO EVEN ECONDARY LINE 5W\TCH.

38 F \G E.

ODD SECONDARY LANE SWITCH.

INVENTOR \NH'RFRED PowELL.

ATTQRNF" March 24. 1925. 1,531,219

W. 'T. POWELL I AUTOMATIC TELEPHONE SYSTEM Filed Aug. 21, '1922 8 Sheets-Sheet 5 COMMON.

INVENTOR NMFRED T. POWELL ATTORNEY 1,531,219 w. T. POWELL AUTOMATIC TELEPHONE SYSTEM Match 24, 1925.

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8 Sheets-Sheet 4 TENS REG)$TER.

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COMMON To E CHAHGE TEST RELAYS,

INVENTOR WIHFRED T. POWELL 63 CODE a w 00 OPERATOR ATTORNEY 8 Sheets-Sheet INVENTOR W\NFRED T. POWELL. BY WMWW.

ATTORNEY w. T. POWELL Filed Aug. 21

AUTOMATIC TELEPHONE SYSTEM March 24. 1925.

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b mim March 24, 1925. 1,531,219

' W. T. POWELL AUTOMATIC TELEPHONE SYSTEM 4 Filed 3 2 1922 8 Sheets-Sheet 6 I' (I *ll'" 2 o; -i N n 2 5 l\ N\ E n m w 1 g J .0 i

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m 10 BY mi \3 E I ATTORNEY March 24.- I925. 1,531,219

w. "r. Pow1 AU'I'OMATIC TELEPHONE SYSTEM l9 .'-PE- .1922 8"Sheets-Sheet 7 CODE CONN CTOR CODE SE LECTQR c005 LINE SWITCH TD RE INVENTOR WINFRED -r. r=owm.\

ATTORNEY TO IHT RRUPTEZR March 24, 1925. I 1,531,219

, w. T. POWELL AUTOMATI C TELEPHONE SYSTEM CONTACT RELAY.

AMMETER.

l 10 VOLTS OVERCHARGE KEY.

VOLTMETER RELAY ms c\ 3 F1G.\O RE m com-:5 TERNUNALS. DIAL FTGJ FIG-Z FlG-3 A 5 FIG-6 INVENTOR WINFRED T. POWELL.

FUSE

fl I ATTORNEY Patented Mar. 24, 1925.

WINFRED T. POWELL, OF ROCHESTER, NEW YORK, ASSIGNOR TO THE STROMBERG- CARLSON TELEPHONE MANUFACTURING COMPANY,

A CORPORATION OF NEW YORK.

OF ROCHESTER, NEW YORK,

AUTOMATIC TELEPHONE SYSTEM.

Application filed August '21, 1922. Serial No. 583,113.

To all 20. mm it may concern:

Be it known that I, vVINrnED T. POWELL, a citizen of the United States, residing at Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Automatic Telephone Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone systems and more particularly to telephone systems employing automatic switches in establishing some portion of a telephone connection.

One feature of the present invention is the provision of novel means for interconnecting the subscribers of a private automatic exchange and subscribers whose lines terminate at a distant manual ofiice. Another feature of the invention resides in the provision of novel means for controlling a code signaling system. Other features will appear from the detailed description and appended claims.

Figs. 1, 2, 3, t, 5, 6 and 8 when arranged in accordance with the chart of Fig. 9 diagrammatically represent a portion of a telephone system wherein Fig. 1 shows a pair of subscribers substations and telephone lines leading therefrom to the movable brushes of a rotary line switch. The fixed contacts of the rotary line switch serve as terminals for primary trunks which lead to secondary line switches shown in F ig. 2. The portion of Fig. 2 above and to the right of the dotted line represents a secondary rotary line switch and its operating circuits, herein arbitrarily designated an odd secondary line switch. Below and to the right of the dotted line of Fig. 2 there is represented a rotary line switch herein arbitrarily referred to as an even secondary line switch. In the lower left hand corner of Fig. 3 there is represented a group of relays and their controlling circuits known as the over-flow controlling means for the bridge circuits all of which are common to the private automatic exchange. In the upper portion of Fig. 3 there is represented the equipment associated with a so-called bridge circuit while in the lower right hand corner of this figure there is represented a so-called sender selector switch which is individual to a bridge circuit and functions to connect its bridge to an idle register sender. In Fig. 4 there are represented two rotary stepping switches serving as tens and units registers of a register sender or number storing device. In the lower left hand corner of Fig. 4 there appears a group of multi-con-tact relays which are common to all the lines of the private automatic exchange, while in the upper left hand corner of this figure there appears a relay with a plurality of contacts, which relay is common to all the lines of a private automatic exchange. Figs. 5 and 6 represent a so-called operators trunk circuit terminating at one end in the jack of the operators switchboard or attendants position and in its other end in the operators line switch which has access to the terminals of the various bridge circuits. Fig. 7 represents the cord circuit at the operators position and functions to interconnect the operator"s trunk circuit and a trunk circuit (not shown) leading to the main exchange (also omitted). Fig. 8 rep-' resents the operating circuits of a so-called code call arrangement, wherein the portion of the circuits above and to the left of the dotted lines represents a code selector for controlling the code signaling, while below and to the left of the dotted line there ap pears a code line switch which functions to connect a code selector to a calling line over which said selector may be controlled. At the right of the dotted line of Fig. 8 there appears a code connector, the purpose of which is to interconnect the bridge circuit which the calling line has seized and the bridge circuit to which the called line is connected. Fig. 10 is a chart showing the number of impulses to be dialed in order to give the corresponding code signal. Fig. 11 shows the operating circuits of an automatic battery charge device by which the battery of the private automatic exchange is automatically charged from the power cir cuits of an alternating current source.

The private automatic exchange of this disclosure as shown isarranged to accommodate one hundred lines which terminate extending from grounded batter in the movable brushes of fifty line switches. These switches have access to twenty trunks terminating in the movable brushes of twenty secondary line switches which in turn have access to ten bridge circuits. lit is also assumed that the live register senders are sur'licient to care for the number of simultaneous calls of this system. It will be understood, however, that the number of lines, primary trunks, secondary trunks, bridge circuits and register senders may be greatly varied without departing from the present invention.

The various switches referred to herein may be of the type substantially similar to that disclosed in the patent to Clement #1,TO7,153 granted August 11, 1914:. The multi-contact relays may be of any design of relay in which the armature on actuation closes a plurality of-contacts.

' It isibeliev'ed that the invention will best be understood by describing the method of establishing a telephone connection from a substation such as A to a wanted substation2 i herein designated B.

It will be noted that the lines leading from substation A and B terminate in the brushes of the same primary line switch but the operation of connecting two telephone lines which do not terminate on the same line switch is not materially different therefrom.

lVhen the subscriber at A initiates a call by removing his receiver from its switch hook a circuit is closed for the line relay 5. winding of this relay, uppermost back contact and armature of cut-off relay 6, over the lower S to 1st of the primary side of the calling line, through the substation circuit A in series, over the upper side of the calling line, upper armature and back contact of cnt-ofl relay 7 to ground. In the event that the brushes 8, 9, 10, 11, 12, 13 and 14 of the primary line switch are resting on the terminals of a pair of idle trunk circuits leading to secondary line switches, these trunks will be seized in the manner-to be indicated. Let it be assumed, however, that one or both of the first pair of trunks tested by the primary line switch are busy, under which condition the cut-off relay 7 will remain inactive due to the fact that its operating circuit is open at this time so that the motor magnet 15 of the primary line switch has its operating circuit closed from grounded battery, resistance, inner armature and front contact of line relay 5, winding, back contact and armature of the motor magnet 15, lowermost front contact and armature of the line relay 5, inner upper back contact and armature of cut-off relay 6 to ground. Under the control of this circuit the motor magnet advances brushes line switch until the test brush 10 encounters the test terminal of an idle trunk, which is characterized by the presence of ground potential thereon. The cut-oil relay '7 is then operated in the circuit from grounded battery resistance, inner armature and front contact of line relay 5, conductor 16, low resistance winding of the cut oil relay 6, in series with the low resistance winding of the cut-off relay 7, test brush 10, test conductor 17 of the idle pair of, trunks, upper armature and back contact of relay 18 to ground. The circuit just described is effective to shunt the motor magnet 15 tostop the operation of the primary line switch and is also effective to energize the cut off relays 6 and 7. With these rela s energized, the lines extending from substations A and B are connected to idle primary trunk circuits but at this time the extension of the line from substation B to the primary trunk circuit is ineffective since its receiver isv on its switch hook. However the operation of the cut-off relay ,7 is effective to extend the calling line from substation A through the upper armature and front contact of relay 7, switch brush 8, conductor 19, middle armature and back contact of relay 20 to ground, while the lower side of the calling line is extended through the uppermost armature and front contact of cut-off relay 6, switch brush 9, conductor 21, inner armature and back contact of relay 20, winding of slow releasing relay 22 to grounded battery. Relay 22 is energized in this circuit and immediately closes an operating circuit for the make busy relay 18, from grounded battery, winding of the relay 18, lowermost front contact and armature of relay 22 to ground. Nith relay 18v energized a locking circuit for the out off relays 6 and 7 is completed from grounded battery, resistance, front contact and armature of relay 18, conductor 17, through the high resistance windings of'the cut oil relays 6 and 7 in multiple, inner front contact and arn'iature of cut-off relay 6 to ground. With relay 22 operated and if the brushes 23, 24., 25, 26 and 2'? are not resting in engagement with the terminals of an idle bridge circuit, the motor magnet 28 of the odd secondary line switch advances its brushes over the terminals of such busy bridge circuits. The circuit for efiecting the advance of the secondary line switch may be traced as extending from grounded battery, resistance, upper front contact and armature of relay 22, winding of the motor magnet 28, its armature and back contact,

inner front contact and armature of relay lower back contact and armature of relay 20 to ground. Idle bridge circuits are in dicated by the presence of ground potential on their test terminals such as 29 so that when the test brush of the odd secondary line switch encounters an idle test terminal a circuit is closed from ground, innermost back contact and armature of relay 30, conductor 31 test terminal 29 test brush 23 inner back contact and armature of relay 32, upper winding of relay 20, upper armature'and front contact of relay 22, resistance to grounded battery. This circuit is effective to short circuit the motor magnet 28 and also to effect the energization of the relay 20. This last relay at its front contact and armature extends the calling line to the brushes 26 and 27 of the secondary line switch whereupon an energizing circuit is closed for the relay 33 from grounded battery, right hand winding of this relay, left hand back contact and armature of relay 35, outer back contact and continuity spring of relay 34-, conductor 36, through the line switch brush 27 to which the lower side of the calling line has already been extended, and over the upper side of the calling line of the extended connection to test brush 2-6, conductor 37 inner" continuity spring and back contact of relay 3%, left hand winding of relay 33 to ground. The relay 33 is energized in this circuit and at its armature and front contact effects the operation of the slow releasing relay 30. This relay at its innermost back contact and armature disconnects the idle ground potential from test terminal 29 and completes a holding circuit for the relay 20 from grounded battery, resistance innermost front contact and armature of relay 30, conductor 3, left hand winding of relay 32, lower winding, front contact and armature of relay 20 to ground. It will be noted that although the holding circuit for the make-busy relay 18 is opened by the deenergization of relay 22, a substitute holding circuit for this relay is now closed at the lowermost front contact and armature of relay 20 to ground. The idle sender selectors of which there is one for each bridge circuit are normally standing in such position that their brushes are in en gagement with contacts of idle register senders. However, as soon as the bridge circuit of F 3 is selected, the relay is operated in a circuit traceable from grounded battery, winding, back contact and armature of the motor magnet 38, winding of relay 35, inner armature and back contact of relay 39, back contact and continuity spring of the trip relay 40, right hand back contact and armature or ringing relay 41, contact 1-2 and armature of relay 30 to ground. ll hen relay 35 is thus operated, ground is applied at its innermost armature and front contact, selector test brush 42 and through the multiple test terminals associated with the register sender Fig. 4. Therefore each sender selector whose test brush similar to 42 is standing in engage ment with a multiple terminal of 42 has an operating circuit closed from grounded battery through a motor magnet similar to 38, its back contact and armature, an armature and contact similar to 44 of a relay like 35, through. a test brush similar to 42 and a multiple test terminal 13 to ground over the path just described therefore, all sender selectors will advance their brushes until the test brushes no longer encounter ground potential.

Also with relay 35 operated the conductor 36 of the bridge circuit which has been connected to the calling line is extended through the left hand armature and front contact of relay 35, sender selector brush la, conductor 46, winding of the impulse relay 4?, secondary winding of the induction coil to grounded battery As soon as-this circuit is completed, a source of dial tone is extended to the calling line to inform the calling party'that a register sender has been seized and that the apparatus is in condition to receive directive impulses corresponding to the designaticn of the wanted subscribers line.

The calling subscriber now proceeds to send impulses corresoonding to the .tens digit of the wanted number. It is assumed that this wanted number is 24-, the calling subscriber than transmits two impulses in response to each of which the impulse relay 4t? retracts its armatures. On the first attraction of the armature of the relay 47, a circuit closed from ground, left hand armature and front contact of this relay, conductor 4:8, tens register brush 4-9 in its first position, back contact armature and winding of the motor magnet to grounded battery. This circuit is effective to advance the tens register into its second position when the change-over relay 52 is energized in series with relay 62 through off-normal contacts 57. W hen the impulse relay, 4-7 deenergizes in reponse to the first tens impulse an operating circuit is extended from grounded battery, winding, back contact and armature of motor magnet 50, brush 4-5 in its second position, conductor 51, back contact and armature of relay a7 to ground. Under the control of this circuit the tens register is moved to position 3. At the close of this impulse, relay 7 is energized and advances the tens re ister into position 4%, over a circuit closed from grounded battery, winding, baclr contact and armature of motor magnet 50, brush 49 in its third position, inner front contact and armature of relay 52, conductor 53, right hand front contact and armature of relay 47, conductor 59, ofi -normal contacts to ground.

In response to the last tens impulse relay l retracts its armature to close a circuit for advancing the tens register into its fifth position. This circuit may be described as extending from grounded battery, winding, back contact and armature of motor magnet 50, brush 49 in its fourth position, outer armature and front contact of change-over relay 52, conductor 58, right hand back contact and armature of impulse relay 47, conductor 59, off normal contacts 60 to ground. It will be noted that after the tens register reaches position 3, an energizing circuit for the change-over relay 52 is extended from grounded battery, winding of relay 62, conductor 63, winding of relay 52, off normal contacts 6 through register brush tf), to ground in multiple with the operating circuit just described for the motor magnet Q (1. At the close of this second impulse the relay 4'? is again energized and the motor magnet is now operated to advance the tens register into its sixth position. This operating circuit is closed fromgrounded bat tery, winding, back contact and armature of the motor magnet 50', brush t9 in its fifth position, inner front contact and armature of change-over relay 52, conductor 53, right hand front contact and armature of relay a7, conductor 59, off normal contacts .60 to ground.

At the close of the tens series of impulses the impulse relay 4;? holes its armatures attracted for a relatively long eriod, so that the operating circuit for relay 52 is interrupted, permitting this relay to retract its armatures. As soon as this takes place the units register is advanced into position two by a circuit closed for its motor magnet from grounded battery, winding, armature and back contact of motor magnet (55, units register brush G6 in its first position, conductor 67, inner back contact and armature of change-over relay 52, conductor 53, right hand front contact and armature of relay 4-7, conductor 59, off normal contacts to ground. The units register is now in condition to receive the units series of impulses, and in response to the first of these impulses the relay 4E7 retracts its armatures to close a circuit from ground, its left hand armature and back contact, conductor 51, units register brush 00 in its second position, back contact, armature and winding of the motor magnet to grounded battery. Under the control of this circuit the units register brushes are advanced into their third position. It should be noted that the energizing circuit for the changeover relay 68 of the units register is closed in multiple with the operating circuit of the motor magnet 65. When the relay 47 attracts its armatures at the close of the first units impulses, the motor magnet is again operated over its initial operating circuit including conductors 67, 53 and 59 to advance the units register into its fourth position. Then the impulse relay 47 again deenergizes and energizes in response to the second impulse of such series, the units register is advanced through position 5 into position 6 and in response to the third and fourth impulse of this series the units reg ister is advanced through positions 7, 8 and 9 into position 10. It should be stated that relay 106 is energized during dialing, over brush 103 and conductor 102 to ground at changeover relays 52 and 68. With relay 106 actuated, relay 30' is held operated and the left hand winding of relay 33 is short circuited to remove the impedance of this relay during imp-ulsing.-

At the close of this series of impulses when the units change-over relay 68 deenergizes, multi-contact test relay 70 is actuated from grounded battery, winding of the relay 70, units register brush 71 in its tenth position, conductor 72, armature'and back contact of change-over relay 68 through both windings in series of relay 73, lowermost continuity spring and back contact of this relay, innermost back contacts and continuity springs of relays 74 and, 75 at the other register senders provided, to ground at the inner back contact, continuity spring of relay 73. This last described circuit is for the purpose of permitting the testing of only one calling line at a time. In the event that some other sender is testing a called line its relay such as 74 or 7 5 is operated to prevent the completion of the circuit ust described. As soon as relay 73 is operated it closes a locking circuit foritsel't through its inner lower armature and continuity spring, while at its uppermost bacl; contact and armature it opens the energizing circuit of the relay 76. This relay is slow in releasingbut before it retracts its armature the test circuit of the called line is closed from ground at the lower armature and front contact of relay 7?, right hand armature, front contact and winding of relay 70, tens register brush 78, contact 79 of multi-contaot test relay 70, conductor 80, inner armature and front contact of cutoff relay 7, primary line switch brush 11, con ductor 81, uppermost armature and contact of relay 82, left hand winding of relay 83, conductor 84, uppermost back contact and armature of relay 'to grounded battery. It will be understood that the relay 85 is not operated at this time due to the fact that its operating circuit is opened at the units register brush 86, since the units ister has not been advanced into an odd position. The relay 88 of Fig. 2 is operated in the circuit just described for a purpose which will be pointed out.

At this point it may be well to explain that if the primary line switch otthe called line is not already ext-ended to a primary trunk circuit the test conductor such. 80 will be extended through the inner armature and back contact of cut-off relay 7, winding of line relay 5 to grounded bat-- tery. The line relay 5 is thus energized and causes the motor magnet 15 to advance the prin'iary line switch brushes into engagex ifilithe inotor inagnet 993s shuntedfand the l; battery, f resistance, lower armature of relay 88, lower winding of rep glay 82, i nieij arinaturei and'front contact of relay 83, test brush 86, test terminal 94, test lconductor 95, sender-selector bru'slii96, con ducftor-.97, front contactland upper armature of relay 77' mgmrma. Relay 82 when'thus i p 'with theloperatin'g oircuit'of the motor ma s 7, unselectable until its registershave been irementwitlr a pair of idle primary trunks ture of relay 83, vinner[upper back contact and'himature of 'relayj 82 to ground. The operation of relayj88'closes an actuating circuit for t-helniotor inagnetQO ofthe even secondary lineswitch, which is traced from grounded battery, resistance, lower contact and ai'niature of relay 88, winding armature and back cont-act of motor magnet 90, front relay 8S,

'ingrelay 55 is" foyer conductor 100', brush 42,arinature and ,contact andv upper-(armature of .ibaclr 'c'ontac't' and ar nature of relay 82to ground; Und er the control of this c rcuit lthe inot'or H I W znd;93 junti1. its testbrjush se caches. the bridge {circuit f to which -the: cal]- At this ,line has already been "extended. rel2ify";:82'.:operates in' a circuit froni grounded front contact and operated glosses alocking circuit for itself from ground through its upper armature front contact andninding, right hand. wind- Y 111g of relay. 83 brush S7,- tern1inal 8,'con- I ductoi' 99, outer armature and front contact of relay tact of triprelay 4:0, winding of ringing relay 4:1 to grounded battery, Relay 82 is thus locked operated and the ringing relay e1 attracts :itscarinatures to apply ringing current-from the source of ringing current 'throiiglrtheright hand winding of the trip I ..1 elay40, front cont-act andarinatureof the r1ng1ng relayel,

oveiz'the selected primary trunk and the called l ne in series, right hand front contact and armature of ringing relay 41, contact 42 and armature of relay to ground. Ringing current is appliedover this circuitto thecalled line until the subscriber thereon removes his receiver from its switch hook, at which time trip relay receives sufiicient current to energize and attract its armatures.v At the r ght "hand armature and continuity spring of relay 40 fi'rounded battery is applied through the resistancc, outermost front contact and armature of relay 2-30 to the holding conductor 99 which maintainstherclay operated durrupted causing this relay closes a ma -net 90 advances its brushes v 1 ing r y battery 30, continuity'spring and back coning this connection. At the right hand back contact and continuity "spring, the energizing circuit of the ringingrelaydl isinterto deenergize, which operation closes 'alocking circuit for the trip'relay 40 fromgrounded'battery, its

winding, lefth'and armature 'and continuity spring, right hand backfcontact and armature of ringingielay 4C1, contact- 42 and armature, of relay 30 to ground. The deener 'ization of the ringing relay 41*;also

b break-.poi'nt'in the called end-of'the connection so 1 that talkin ficurrent is "supplied to the called 'subscri er .through both windings in, series' of thezrela-y 34.; This energizes the relay 34: and opens the 1mpuls-' ing circuit, which-"has previously-been extended to'thel register'sender off liigg 4.

As soon as'the ringing i'lay l attractsits armatures the holding oircu ito'f the relay 35 is opened I causing this relay 't'd-deenergize, whereupon, the holdingl'circuit {for-"the" holdbroken{'wliicl1'= was completed :norina-l positionl This; is accomplished in the-following" I 'ina 3fiiier; The tens register" is restored in circuitjclosed from grounded '1 win'din v contact and armature thereof, 7 off norontact's 6A5 *whichjarelosed in positions condiictoF56, middle-'contact and-armature of -relay;5 5,"- conductors 54 The relay I62 i's* held operated in 'multiple order torender the register sender gutf it -"motor" magnet '50, I

stored to normal'positioii. Thief circuit exbaclr'oontact of magnet 65, off-normal contacts 1'01", inner" back contactand armature of-rela-ybh to' ground. The relay'62 is energized in multiple, with the operating-circuit of the units register magnet and at its armature and"front contact applies ground to conduct-or 100-torender this register sender unselectable until its registers are restored to normal." I

v At the close of the conversation when the calling party replaces his receiver on its switch hook, the battery feed relay 33 deenergizes and shortly afterwards theslow releasing relay 3O retracts its armatures to open the holding conductor 81. This causes the deenergization'of the holding relay 2O .ilea'se; of the primary line switch-,

which releases the odd secondary line switch and also opens one branch of the circuit of the relay 18. The release of the relay. also interrupts the holding conductor 99 .which was maintaining the even secondary line switchv operated. The opening of this circuit causes relay 82 to deenergi-ze to effect the release of the secondary line switch. Also the release ofrelay 82 opens the other branch of the holding. circuit/of" relay..l8 which deenergizes toeffect. the ,deenergization of relays (i-and? which cause,- there 76 deenergizes, an-operating circuit-Qis closed g-for the busy test relay 89, of. Fig 3: from in the manner already described. It will, of course, be understood that the setting of the units register completes an energizing circuit for the relays 108 and 145 of the group of lnulti-contact relays so that the test circuit to the operators position is extended from ground at the. armature and front contact of relay 77, armature front. contact and winding of relay 76, brush 78, ;ccnductoi: 109, contact 110, armature and contact 111,1conductor112 which conductor 1 continued tofthe upper left hand corner IofFigQQG left hand, armature and back of slow releasing relay 115to groundetl'battery' Relay- 11 5'is energized in' this circuit and atfits right hand armature and front ,con'tactv causesjthe. operationof relay 116. This last named relay when energized, closes an. operating circuit for the motor magnet 117' of the operators line switch. This cirfcuit-i may be described as extending from .ic ontactfo' frelay' 113, conductor llhwinding .I grounded-battery, resistance, left hand front contact and armature of relay 116, winding,

armatureand back contact of motor magnet grounded battery,.winding ofthis relay, its I {117, right hand front contact and armature YCOIlll-inlllt) spring and backcontact, middle armature and front contact] of. relay :35,

" selector-brush 152, conductor 104-, backeontact and armature -.of relay, 76 dowerflfroht contact and armaturepfrelay o, to, ground. 1- Relay 39 is energizegliinr this. c11f U i,t ,,and s locked te thrbueltita'e e efiit 1 springtoground:atcontactgggand'arfnature ,1, 1'

BZlis-t-hen applied-tothecalling line'thr A the upper armature, and. front, ,contafeh ,of relay 39 and. conductoriil05 s ,The subscriber. on-hearing .this busy toneknows of relay; 30. A'source.of busyton'ecu L that the .wanted line cannot wintertime replaces. his: receiyer' on: its t switch, hook... to

restore the connection until somelatertti'mje.

:Ihe energizati-onofrelay 39opens the holdmg circuit ofrelay':3 5.which deenergizes to effect the releasev of ,theiregister sender. of

1 Fig; has already described. .4

Automatic call to Moda ofiz'cc," Let it be'assumed that the-subscriber. 'at

A desiresto call a subscriber located at the --n1ain. office, it then becomes necessaryjf'or I the subscrlber at A to signalthe pr vate branchexchange-- operator, this. accompllshed-bydialing ;OO.. When-. .the subscriber-initiates such a calhthe callinggli'ne the-subscriberfirst dials-0 to adigance the tens register: into position-22 and then dials O a' second.timeztoasetthefiunitsi register into position 22, all of which takes place ;of relay11(, upper back contact andfarmatureloflrelay' 11 8' 'to ground. Under the control: o flthis circuit, the "motor: magnet ll'lia dwjancesits brushes 119, 120, 121, 122 123 byer', the contacts of 'various brid e kg-fire the bridge circuit to whicliitlie.

-1, Qu i e ibf my; resistan e; le t a mm contadti ant armamrefpi relay '116 ":'low'er of relayf 118', inner ar'matu're and front? 'ciontaa I brie-lay 1'15, br'ush '120,'*test ycoiitac-t' 124,1} conductor 95," sender selector :ibjr u'sli fifi'," conductor97, upperfront contact armature ,ofrelayfZT to'grou'nd. This circuit isalsoefi'ective' to shunt the motor n1agnet- 117 to stop the operators line switch withits brushes inengagement with- .tlie bridge-circuit now connected to the calling. line. vThe relay 118 is thus energized '-and. closes a; locking circuit for itself.

through its inner upper'armature, front con- ",t'act and winding, line switch brush 119, terminal 125, conductor 99, outermost armature and front contact'of r elay' 30,fright timej relayj' 118" is operated from 'l1and',continuity spriugand back contact-of itrip relay. ,40, winding of ringing relay all to. grounded battery. U I ,7 1 ,The ringing relayisalso energized at this time andcloses the ringing'circuit including lithe right hand winding of th'e trip relay -10,

; left} hand. front contact and armature of the au'ingingfrelay, over the lower side ofthe bridge circuit, operators line switch brush 122 of Fig; 6', inner lower front contact and armature of relay 118, right hand continuity ;;;spring and back contact of relay 126, lower most armatureand back contact of relay through the source of current, left hand winding of hills relay inner back contact and armature of relay 127, left hand back contact and continuity spring of relay 126,

lay 31. As soon as the relay 128-is operated it closes an energizing circuit for the relay .129, extending from grounded battery, winding of this relay, jack contacts 130, conductor 131;..win ding of relay'132, armature and fronticontact of relay 128 conductor 133, jack contacts 134 and 135 -to ground.

If. the calling subscriber is entitledi to a connection; with. the main ofiice' his line [switch is connected with .a brush such as" 12- :ofF ig. 1 which connects ground potential at the uppenarniature and iront 'c'ontactio'f the cutoff relay. fii jover conductor 137 armature and frontcontact otrela y 32, conductor 138, secondary line-switch brush 25, 'cong 'dnctor 139, terminal 140 thence the circuit 5 is completed through operatoris line switch brush 121, uppermost .arxnature and fiont contact of relay 11S, conduct-or 141, winding i of relay. 142 to. grounded battery, Lamp f 1 13, is thenoperated in a circuitlcompleted through front contacts and armatures of rclay 142 and 129. It willbe understood that' the signals 14:3 and 1 14: may be of different character such as different colors ordifierent locations so that on noting this [signal theoperator .will know whether or not the subscriber calling from the private automatic exchan e is entitled to the connection with the main ofiice.

Thesoperator on noting sleeve of-the jack J, a break point is closed in the operating circuit of the answering supervisory lamp 198. This lamp is not lighted. howe'iver, at this time since the supervisory relay 1% is energized from grormdedbattery left hand winding of this relay, lower side of the cord circuit, ring contacts of theiplug conductor 131, imped- 2111600011132; arniatureand front contact of therelay 13S. conductor 133. righthan'd armature and front contact of relay 14:2, tip] contacts of plug and jack right hand wind- 1r ot relay 199 to ground.

' After inserting the answering plug into through'the connection so'j extended. Such I A '80 Iof lamps 14:3 ia'nd' 144 arise-r n p 144: n uns ern .c mi et ns in a f standard pings a'ndj' a1 e also"talking{battery s suppliiedto ."f icu t'. l i i slif 1 h? effect the rele o gtioned relay-a ts out contact open t that the lamp 1-13 is lighted. knows that this calling subscriber is entitled to service through the main exchange and she therefore inserts the .answer- Call from maia-iewoltange thew-private the ack of" the] calling trunkthe K opera-tor throws her listeningkey '11.: K; {to asgEertain the number of the Wanted subscribr,where upon she inserts the "plug "P" into' the' jack of a trunk leading to the main office (not shown). The jack J of'thisfdisclosurefis constructed to'cooperate with a plugbif'suh design that the tipfcontact of the phi'g opens tip contactsin the'trunli" conductors leading to the calling line sothat if -i-ny 142 is not operated it will be impossible forthccalling subscriber I who is "not entitl'ed to :1- connection with" the main exchange} talk an arrangementis provided tornake the diserinnn ation between subscriber's" entitled 'to 3. 00111180131011 at the main exchange and those -notentitled to such a conriht i'onfind epend ent of operators(control. It-will, (Sf-course,

to extend suchfl'oi'iginatih'g calls as light the t the automatic ,disn iaj jorn'itted and nigh-yea. In this mena i 1 1.3-. which has been maintain 'g'r elay 118fof'the .operators line switch rgiz ed, Relay 11S thereupon deenergizes" and 'releasesflthe operatorsline, switch-ion use on a succeeding call. The releaseof 118 also'efi'ects the deenergizationof relay '128'fwhich relay effects the release lo f su p eryisory relay I 19 9 an d lamp 198 is lighted toinclicate' to the lqp'e rw gizes" in the manner pi'eyiolu'sly described to for that it 'is'jtirne i or eiscomieamn; E The operator then reinovesthe calling plug from 110 the jack of the trunikto the distantfofiice and the answcring' jplug P of the hord circuit which she hasused from the a'cli to restore the connection; n5

automatic exchange;

the lighting of this lamp inserts the plug P into the ack of the operators trunk (Fig. 5) and after throwing the listening key L. K. to connect her head set to this trunk she ascertains the number of the wanted line. The attendant operator now inserts the plug P into the jack J which serves as a terminal of the operators trunk connected to the private automatic exchange. This closes jack contacts 201 by which a circuit is closed from grounded battery, winding of relay 127, right hand back contact and armature of relay 113, jack contacts 201 to ground. Relay 127 on energization closes a locking circuit for itself, through its inner upper front contact and armature, which circuit is independent of the armature and backcontact of the relay 113. This locking cirsuit also includes the upper winding of the polarized relay 202 in multiple. Relay 202 is not operated, however,,until the called party answers which reverses batteryover the trunk by the operation of the relay 3%.- Relay 127 disconnects the relay 128 which relay is used when this trunk functions to extend a call from a private automatic sub scriber to a subscriber at the main exchange. Relay 127 at this time also closes a bridge across its trunk to the-operators line switch which bridge includes the lower winding of the relay 202 and the impedance coil 203. The relay 116 of Fig. 6 is also energized in. series with the relay 202 and coil 203 and when thus operated closes an operating circuit for the motor magnet 117 by which thebrushes 119 to 123 inclusive of the operators line sw'itchare advanced to seize the originating terminalsof an idle bridge circuit.

hen such an idle bridge circuit is located the relay 118 is operated in the manner already described to disable the relay 116 and to close break points in the operators trunk circuit. At this time a circuit is closed from ground at the innermost upper armature and front contact of relay 118, conductor 205, left hand winding of relay 113 to grounded battery. This relay serves to extend the operators test circuit 112 through the left hand armature and front contact of relay 113 conductor 206, outermost armature and back contact of relay 115 to the next idle trunk switchto render said trunk switch selectable on a succeeding call.

Since the operators line switch which has thus'seized the bridge circuit is resting on an originating set of terminals, line switch brush 121 is connected to ground which operates the. relay 142 to bridge a break point in the tip conductor of the operators trunk opened by the large tip of the op erators cord circuit plug. The operator now depresses the common dial key 207 which energizes the relay 126 to connect the dial 208 across the operators trunk.

"to grounded battery.

The wanted number is now dialed and the fast relay 209 and the slow releasing relay 126 are held operated during each rotation of the dial. Impulses from the dial 208 are transmitted over the operators trunk and through the selected bridge circuit to a reg ister sender similar to that shown in Fig. 4, whereupon the testing of the called line is effected, and if idle, primary and secondary line switches extend this line to the terminating end of the bridge circuit to which the operators trunk is connected. Thereafter the ringing, talking and releasing operations are effected in the manner already described.

If the dial key 207 is restored before the dial completes its operation for the last digit, ground at'the back contact of the dial key is extended through the front contact of the fast operating relay 209', through the front contact and armature of relay 127, armature and back contact of relay 210, winding of relay 126 to grounded battery which maintains the relay 126 energized. lVhen, however, the dial completes its operation and the dial key is restored, ground at the back contact of the dial key is extended through the armature and back contact of relay 209, inner armature and front contact of relay 126, winding. of'relay 210 Relay 210 is operated inthis circuit and closes a locking circuit for itself through its lower front contact and armature as long as the operators cord circuit is in the ack J.. The energization of relay 210 effects the re lease of'relay 126, which disconnects the dial 208 from this trunk. as long as the plug is in the jack J.

The response of the called party actuates the relay 3a of Fig. 3 which reverses the direction of battery supplied over the terminating end of the bridge circuit and thereby effects the operation of the polarized relay 202 which last named relay provides supervision on the operators cord circuit.

Code call.

In the present system provisions are made for-locating executives of the plant who happen to be away from their desks at the time when they arewanted. Such an arrangement is known as acode call and consists of signals such. as lamps or gongs located at various parts of the office or factory and of. suit-able actuating mechanism by which the lamps. or gongs may-be operated according to a predetermined code of long and short impulses, one code being assigned to each of the persons to be called.

Let it be assumed that the subscriber at A desires to locate a person who may be reached 1 by the code call, the subscriber first removes his receiver from its switch hook. to extend his line through primary able to send out the code call the subscriber is instructed to dial 09 which. is effective to actuate the multicontact relay 145 of the group of multi-contact relays so that a test circuit is then extended to register brush 78, conductor 10-9, contact and armature 110 of relay 145, contact and armature 146 of relay 108, conductor 147, lowermost armature and back contact of relay 148, Fig. 8, winding of slow releasing relay 149, selector brush 150 in its first position, outer armature and back contact of relay 151, resistance 152 to grounded battery. The relay 149 is thus operated and closes an actuating circuit for the motor magnet 153 of the code line switch by which its brushes 154, 155, 156 and 157 are advanced to lo cate the bridge circuit to which the calling line has been connected. The circuit of the motor magnet 153 is closed from ground at the inner armature and back contact of relay 148, inner armature and front contact of relay 149, back contact, armature and winding of the motor magnet 153, uppermost front contact and armature of relay 149, resistance 152 to grounded battery. lVhen the calling bridge circuit is located, the motor magnet 153 is shunted and the relay 148 is operated in a circuit completed from grounded battery, resistance 152, uppermost armature and front contact of relay 149, upper winding of relay 148 conductor 158, code line switch brush 157, conductor 159, conductor 95, sender selector brush 96, conductor 97, front contact and upper armature of relay 77 to ground. The relay 148 when operated closes a locking circuit for itself from ground its lower arn'iaturc, front contact and lower winding, conductor 160, line switch brush 154, conductor 99, outer armature and front contact of relay 30, continuity spring and back contact of relay 40, winding of ringing relay 41 to grounded battery.

As soon as the relay 148 is energized it opens the energizing circuit of relay 149 causing it to release. The operation of relay 148 also connects the left hand winding of the impulse relay 161 in multiple with the calling line, and this relay operates in parallel with relay 33 of the bridge circuit which has been connected to the calling line. A circuit is now closed from ground at the inner lower armature and front contact of relay 148, conductor 162, code-selector brush 163, back contact and armature of motor magnet 164, armature and front contact of relay 161, code selector brush 165 in its first position, back contact and middle armature of relay 166,

winding of the motor magnet 164 to grounded battery. Under the control of this circuit the code selector is advanced to position 2 as soon as the code selector has been connected to the calling line, the call ing subscriber then proceeds to dial the number of impulses corresponding to the codes assigned to the wanted party.

In response to each of the impulses corresponding to the code number, an impulse circuit is closed from ground at the armature and front contact of relay 148, conductor 162, brush 163, left hand armature and back contact of impulse relay 161, brush 165, back contact and middle armature of relay 166, winding of the motor magnet 164 to grounded battery. If six impulses are transmitted for the first digit, the switching relays 167 or 168 will not operate due to the fact that the motor magnet 164 advances code selector brush 150 past the contacts to which energizing circuits of these relays are connected. However, if No. 5 is the first digit the motor magnet 164 advances the code selector brushes into such position that brush 150 completes an operating circuit for the switching relay 167 as soon as the change-over relay 151 deenergizes. This circuit extends from ground, left hand winding of relay 167, brush 150 in its seventh position, outer armature and back contact of relay 151, resistance 152, to grounded battery.

Relay 167 when thus energized closes a locking circuit for itself from ground, through its left hand winding, front contact and armature, brush 169, conductor 170, resistance 152 to grounded battery. When No. 4 is dialed for the first digit, the brush 150 is advanced into its sixth position whereupon relay 168 is operated through its left hand winding and thereupon closes a locking circuit for itself through brush 169 in the manner already indicated. However, if No. 3 is the first digit dialed, the brush 150 is advanced into its fifth position where operating circuits are closed for the relays 167 and 168.

In response to the next series of impulses the motor magnet 164 is operated in the manner already described to advance the brushes of the code selector a desired number of steps. By reference to the table shown in Fig. 10 itwill be noted that the code selector has twenty-five different posi tions and with two switching relays such as 167 and 168 it is possible to obtain 12 different codes by dialing two series of code impulses. The small a? appearing in this table indicates the position of the code selector brushes just prior to the time when they begin their advance to actuate a code alarm.

As soon as the two series of code impulses have been received by the code selector the change-over relay 151 again deenergizes. At this time, however, the brush 163 of the code selector has been advanced past its eighth position, so that the switching relay 166 is now operated in a circuit closed from grounded. battery, through its lower wind ing, back contact and armature of relay 151, selector brush 163 in some one of the positions 9 to inclusive, conductor 162, lower front contact and armature of relay 14-8 to ground. The relay 166 in turn closes a locking circuit for itself from ground through. its upper winding, front contact and armature, selector brush 169, conductor 176, re sistance 152 to grounded battery. Also with the switching relay 166 operated, a circuit is closed from ground at the interrupter (not shown) conductor 171, lowermost front contact and armature of relay 166, winding of the motor magnet 164 to grounded battery. I

Under the control of this circuit the motor magnet 16 1c advances the brushes of the code selector and while the brush 150 is passing through its position 9 to 25 various long and short ringing signals are produced by the gongs such 172, depending on the original position of the brush 150 and also depending upon which of the switching relays 167 or 168 is operated. Under the control of the mentioned circuit, the motor magnet 16% advances the brushes of the code selector into their normal position whereupon relays 166, 167 and 168 are released but the code selector takes a preliminary step into its first position so that the calling party again dial the code number to repeat the code ringing without the necessity of releasing the connection and again dialing #09 to select the code circuit.

It will be noted that the code selector brush 156 disconnects battery from relay fl t-,9 in all its positions except position one, this is to prevent the switch from being seized until it is in its normal position. It will also be seen that when the relay 166 OpQIHtGS, the wanted code signal is produced in full, even though the calling party releases during the time that the gong 172 is being actuated.

When the wanted party hears his code signal he proceeds to the nearest telephone and dials No. 09 this is accomplished in the following manner. On removing the re ceiver from its switch hook, the primary line switch of the answering line seizes a secondary line switch which in turn extends the calling line through an idle bridge circuit and a sender selector to an idle register sender. This register sender is adjusted in response to the #09 to extend the testcon ductor 1417 through the lowermost armature and front contact of relay 14-8, armature and back contact of relay 149, winding of slow releasing relay 173, conductor 174, uppermost back contact and armature of relay 1.75, conductor 176, resistance 152 to grounded battery.

Relay 173 is operated in this circuit and closes an actuating circuit for the motor magnet 177 which advances the brushes 178, 179, 180 and 181 of the code connector to connect the answering line and the bridge circuit'to which it is connected to the calling line and to the bridge to which it is connected. When this connection is completed relay 175 is operated from grounded battery, resistance 182, inner armature and front contact of relay 173, lower winding of relay 175, code connector brush 181,.conductor 183,a conductor similar to 95 of the bridge circuit to which the answering line is connee-ted, brush 96, conductor '97 and upper contact of relay 77 to ground; all of which circuits are associated with the sender selector and register sender-to which the answering line is connected.

Nhen relay 175 operates it interrupts the energizing circuit of relay 173 which deenergizes. It will be seen that the called and calling lines are now connected in multiple through condensers of the code connector. The test circuit 09 of the code signaling tests busy until both the calling and answering parties release the connection.

The ringing is not tripped on the bridges used in this connection, but this operation" is not necessary because there is no line circuit on the terminating end of either bridge circuit.

Overflow circuits.

It will be noted by reference to Figs. 1 and 2 that overflow circuits are provided. This is for the purpose of preventing primary and secondary line switches from rotating continuously when all the primary trunks and all of the bridge circuits are in use. The operation of the primary overflow circuit is as follows. As long as any primary trunks are idle, the relay 187 is inert due to the fact that it is short-circuited by ground at the lower armature and back contact of some one of the relays 18 associated with a primary trunk circuit. For this reason the stopping condition is not present on the over-flow terminals. \Vhen, however, all the primary trunks are engaged all of the relays similar to 18 are operated and the relay 187 is then actuated in a circuit closed from ground, winding of this relay, armature and front contact of relay 18, conductor 188, resistance to grounded battery. At the lower armature and front contact of relay 187 ground is applied to the terminal 189 of the overflow trunk so that when the brush 10 of the primary line switch of the calling line encounters this terminal, the primary line switch is stopped as has been described and the calling line is extended through brushes 8 and 9, through both windings of relay 190 in series to ground and grounded battery respectively. Relay 190 is thus energized and effects the operation of relay 191. lVith the relays 187 and 191 thus energized, holding battery is extended through the front contacts and armatures of these relays, over conductor 192, test terminal 189, test brush 10, through the high resistance windings of relays 7 and 6, upper front contact and armature of relay 6 to ground. I

The calling subscribers line is thus held in engagement with the over-flow trunk as long as the calling subscriber continues to keep his receiver from its switch hook and a busy tone is applied from the source of busy tone current BZ'and upper winding of relay 190 to the calling line. Similarly while any of the of Fig. 3 are idle, ed by ground at the armature 194: of relay 30. hen, however, all the bridge circuits are in use all relays similar to 30 are operated so that the relay 193 is then energized in a circuit closed from ground, lower winding of this relay, armature 194 and front contact of relay 30, lefthand winding of relay 185 to grounded battery. lVith the relay 193 thus operated stopping potential is applied to test terminal 195 of the overflow bridge which causes the secondary line switch to stop on the over-flow bridge circuit and thereby effects the operation of relay 196. This actuates the slow releasing relay 197 and holding battery potential is applied through resistance 198, and through the armatures and front contacts of the relays 193 and 197 to the test terminal 195.

Battery charging arrangement.

In Fig. 11 there is shown an arrangement for charging the direct current battery of the private automatic exchange from a source of alternating current. In this arrangement any well known current recti fying device such as is indicated at ,250 may be employed for rectifying the source of alternating current to charge the battery 251. In addition a voltmeter relay of well known construction is employed and functions when the volta 'e of the battery 251 becomes too low, to c ose contacts 252, and when the voltage of the battery 251 has reached a predetermined maximum amount, contacts 253 are closed as will be described.

The relay 25 1 herein shown is provided with two windings and is known as a carbon contact relay because its contacts are of carbon to prevent serious arcing when the power circuits are opened.

In the operation of this arrangement, when the contacts 252 of the voltmeter relay are closed due to the fact that the voltbridge circuits relay 193 is short-circuitage of battery 251 has reached a predetermined minimum amount, a circuit is closed from ground, contacts 2 2, winding of relay 255 to grounded battery. Relay 255 is thus energized and closes a locking circuit for itself from grounded battery, its winding, conductor. 256, lower back contact and armature of relay 257, lower armature and front contact of relay 255 to ground which maintains this relay operated until the battery 251 is fully charged or until the charging is stopped manually. The energization of relay 255 completes an operating circuit for the carbon contact relay 254, which circuit is closed from grounded battery, winding of this relay, upper front contact and armature of relay 255, upper back contact and armature of relay 257 to ground. Relay 254 when thus energized closes contacts 258 and259 thereby completing a charging circuit from the source of alternating current over, conductor 261, contacts 259 and 258, through the rectifier 250, ammeter 262 to one side of battery 251 and from the grounded side of battery, through the rectifier 250, conductor 263 to the source of alternating current. Under the control of this circuit battery 251 is charged until a predetermined voltage isreached, whereupon the voltmeter relay closes its contacts 253. This completes a circuit from ground, through contacts 253, overcharge key contacts 270, winding of relay 257 to grounded battery. Relay 257 is operated in this circuit and opens the holding circuit previous ly mentioned for the relay 255. Relay 255 then deenergizes and opens the actuating circuit' of the carbon contact relay 254which in turn deenergizes to open the power circuit. In the event that it is desired to charge battery 251 before'the voltage has reached the predetermined minimum a start key 265 is depressed manually to close a circuit for the relay 255 which functions as already described to start charging the battery 251. In the event that it is desired to stop the charging independently of the automatic control, the star key and the overcharge key are both depressed to complete an actuating circuit for the relay 257 through contacts 267 of the over-charge key and contacts 266 and 268 of the start key to ground. Relay 257 is thus energized and opens a 100 ing circuit of relay 257 to stop the charging of the battery as has been described.

What is claimed is 1. In an automatic telephone system, a plurality of telephone lines, one or more signals, actuating means for operating said signals according to code, means including one or more non-numerical switches to connect a telephone line to said actuating means to directively operate the same, a second line, and means controlled over said second line for disabling said actuating means and for! connecting said first and second lines through non-numerical switches only.

2. In an automatic telephone system, a plurality of telephone lines, a plurality of bridge circuits, a plurality of number-storing devices, means including primary and secondary non-numerical switchesoperating responsive to the initiation of a call on a telephone line for connecting said line to a bridge circuit, means for connecting an idle number storing device 'to the selected bridge circuit, a code signaling device, means controlled over the two sides in series of the calling line for selectively opera tingthe con- .uected number storing device, a switching mechanisn'i for connectingthe code signalingdevice to the calling line under the control of thevoperated number-storing device, means controlled over the calling line for selectively operating said code signaling device, and means controlled from any of said other lines for disabling said code-signaling device and for connecting said last mentioned line to said calling telephone line.

3. In,v an automatic telephone system, a plurality of telephone lines, a plurality of link circuits, a'code signaling device, means including a calling lineand a selected link circuit for directively operating said code signaling device, means including a second telephone line and a second link circuit for disabling said code signaling device, and means including a non-nun'ieirical switch for interconnecting said first and second mentioned link circuits.

4. In an automatic telephone system, a plurality of telephone lines, a plurality of link circuits, means for intercoimecting a calling line and a link circuit, code signaling means, a code signaling'switch, means in cluding a calling line anda selected link circuit for directively operating said code signaling switch, said last mentioned means being arranged for continuing the operation of said switch at will to actuate the code signaling means in accordance with the setting ot said code signaling switch.

5. In an automatic telephone system, a plurality of telephone lines, a plurality of link circuits, non-numerical switches for interconnecting said lines when calling with idlelink circuits, one or more code signals, a code selector for variably operating said code signals, means including a. calling telephone line and a selected link circuit for selectively operating said code selector, a plurality of'relays anranged to be selectively operated under the control of said code selector, means including said code selector and said actuated relays for selectively operating said code signals, and means controlled over a second line for disabling said code selector.

6. In an automatic telephone system, a

" operators plurality of telephone lines each provided with a calling dial, aplurality of link circuits, non-numerical switches for intercom necting said lines when calling with idle link circuits, one or more code signals,'a code selector for variably operating said signals, means including a calling telephone line and a selected link circuit for selectively=-operating said code selector, a plurality'ot relays anranged to be selectively operated under the control of said code selector and means including said code selector-and said actuated relays for selectively operating said code signals, means including the dial of the calling line for repeating the operation of said code selector, means controlled over a second line for disabling said codeselector, and means including non-numerical switches only for interconnecting said second line and said calling line.

7 In an automatic"telephone system, an position, a plurality of telephone lines, each provided with an impulse sending device, a plurality of link circuits, nonnumerical switches, means including: non numerical switches for connecting said tele phone lines when calling to idle link circuits, a plurality of register senders, means elfective on the seizure of a link circuit for associatingan idle register sender therewith, means including said impulse sender and the calling telephone line for selectively operating said register sender to select the operators position, means responsive to such selection to extend the calling line and selected link to "the operators position through non-numerical switches exclusively, and means at said operatorsposit-ion for extending the calling telephone line and its selected lin'k circuit to a wanted telephone line.

8. In a telephone system, a plurality of telephone lines, a plurality of link circuits, means including non-mm'ierical switches for interconnecting a telephone line and a link circuit, an operators position, a plurality of 'operators trunk circuits atsaid operators position, means including non-numerical switches for connecting operators trunk circuits to link'circuits, a plurality of register senders, means for associating an idle registersender'with a link circuit, a dial impulse sending device at said 'operators position common to= said operators trunk circuits, a common dial key at said operators position for pulse sending device to a selected'trunk circuit, said, impulse sending device being effective to selectively actuatesaid register sender, means responsive to the setting of said register sender for extending a wanted telephone line'th'rough a selected link circuit toth'e operators trunk circuit, and means for causing said impulse sending de vice to complete its operation of sending a connecting the dial imloo 

